Backspace in modal doesn't make browser navigation (#13180)

In a modal window if focus is not in an editable component
the backspace default action is prevented.
Also when focus is on bottom or top components.

Change-Id: I53f0922e5ddff142e2d540be52e70c7d23d1b585

2 files changed, 33 insertions, 8 deletions

diff --git a/client/src/com/vaadin/client/Util.java b/client/src/com/vaadin/client/Util.java
index 306f26b1af..1cdd8fb458 100644
--- a/client/src/com/vaadin/client/Util.java
+++ b/client/src/com/vaadin/client/Util.java
@@ -1262,6 +1262,25 @@ public class Util {
     }
 
     /**
+     * Gets currently focused element and checks if it's editable
+     * 
+     * @return true if focused element is editable
+     */
+    public static boolean isFocusedElementEditable() {
+        Element focusedElement = Util.getFocusedElement();
+        if (focusedElement != null) {
+            String tagName = focusedElement.getTagName();
+            String contenteditable = focusedElement
+                    .getAttribute("contenteditable");
+
+            return "textarea".equalsIgnoreCase(tagName)
+                    || "input".equalsIgnoreCase(tagName)
+                    || "true".equalsIgnoreCase(contenteditable);
+        }
+        return false;
+    }
+
+    /**
      * Kind of stronger version of isAttached(). In addition to std isAttached,
      * this method checks that this widget nor any of its parents is hidden. Can
      * be e.g used to check whether component should react to some events or
diff --git a/client/src/com/vaadin/client/ui/VWindow.java b/client/src/com/vaadin/client/ui/VWindow.java
index 7223e4ac83..58e7a83012 100644
--- a/client/src/com/vaadin/client/ui/VWindow.java
+++ b/client/src/com/vaadin/client/ui/VWindow.java
@@ -16,6 +16,8 @@
 
 package com.vaadin.client.ui;
 
+import static com.vaadin.client.Util.isFocusedElementEditable;
+
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -178,8 +180,6 @@ public class VWindow extends VOverlay implements ShortcutActionHandlerOwner,
     // Prevents leaving the window with the Tab key when true
     private boolean doTabStop;
 
-    private boolean hasFocus;
-
     /**
      * If centered (via UIDL), the window should stay in the centered -mode
      * until a position is received from the server, or the user moves or
@@ -420,6 +420,7 @@ public class VWindow extends VOverlay implements ShortcutActionHandlerOwner,
                 Id.of(headerText));
 
         // Handlers to Prevent tab to leave the window
+        // and backspace to cause browser navigation
         topEventBlocker = new NativePreviewHandler() {
             @Override
             public void onPreviewNativeEvent(NativePreviewEvent event) {
@@ -429,6 +430,10 @@ public class VWindow extends VOverlay implements ShortcutActionHandlerOwner,
                         && nativeEvent.getShiftKey()) {
                     nativeEvent.preventDefault();
                 }
+                if (nativeEvent.getEventTarget().cast() == topTabStop
+                        && nativeEvent.getKeyCode() == KeyCodes.KEY_BACKSPACE) {
+                    nativeEvent.preventDefault();
+                }
             }
         };
 
@@ -441,6 +446,10 @@ public class VWindow extends VOverlay implements ShortcutActionHandlerOwner,
                         && !nativeEvent.getShiftKey()) {
                     nativeEvent.preventDefault();
                 }
+                if (nativeEvent.getEventTarget().cast() == bottomTabStop
+                        && nativeEvent.getKeyCode() == KeyCodes.KEY_BACKSPACE) {
+                    nativeEvent.preventDefault();
+                }
             }
         };
     }
@@ -1302,10 +1311,11 @@ public class VWindow extends VOverlay implements ShortcutActionHandlerOwner,
 
     @Override
     public void onKeyDown(KeyDownEvent event) {
-        if (hasFocus && event.getNativeKeyCode() == KeyCodes.KEY_BACKSPACE) {
+        if (vaadinModality
+                && event.getNativeKeyCode() == KeyCodes.KEY_BACKSPACE
+                && !isFocusedElementEditable()) {
             event.preventDefault();
         }
-
         if (shortcutHandler != null) {
             shortcutHandler
                     .handleKeyboardEvent(Event.as(event.getNativeEvent()));
@@ -1322,8 +1332,6 @@ public class VWindow extends VOverlay implements ShortcutActionHandlerOwner,
 
     @Override
     public void onBlur(BlurEvent event) {
-        hasFocus = false;
-
         if (client.hasEventListeners(this, EventId.BLUR)) {
             client.updateVariable(id, EventId.BLUR, "", true);
         }
@@ -1331,8 +1339,6 @@ public class VWindow extends VOverlay implements ShortcutActionHandlerOwner,
 
     @Override
     public void onFocus(FocusEvent event) {
-        hasFocus = true;
-
         if (client.hasEventListeners(this, EventId.FOCUS)) {
             client.updateVariable(id, EventId.FOCUS, "", true);
         }